Interior permanent magnet motor

Abstract

An interior permanent magnet motor includes a rotor and a stator. The rotor includes a rotor core. The rotor core is formed by laminating steel plates each including pairs of magnet insertion holes and pairs of cutouts. Each pair of magnet insertion holes includes two magnet insertion holes that are arranged in a V-shape, the wide end of which is relatively closer to the outer edge with a support portion located in between. Each pair of cutouts is formed at q-axis ends of the corresponding magnet insertion holes, and includes two cutouts connected to the outer edge of the rotor core. In a state where the permanent magnets are inserted in the magnet insertion holes, a gap is formed at a d-axis end of each magnet insertion hole.

1 . An interior permanent magnet motor, comprising:
 a rotor including a rotor core having an outer edge, the rotor core being formed by laminating steel plates each including a plurality of pairs of magnet insertion holes, each pair of magnet insertion holes is formed of two magnet insertion holes arranged in a V-shape, a wide end of which is relatively closer to the outer edge of the rotor core;   a plurality of pairs of permanent magnets embedded in the pairs of magnet insertion holes, each pair of permanent magnets is formed of two plate-like permanent magnets arranged in the V-shape and such that corresponding poles face each other; and   a stator around which a coil is wound, wherein   each magnet insertion hole includes a d-axis end located in the vicinity of a d-axis, and a q-axis end located in the vicinity of a q-axis,   the rotor core is formed by laminating only the steel plates in which the q-axis ends of all the magnet insertion holes are connected to the outer edge of the rotor core by cutouts, and   when the permanent magnets are inserted in the magnet insertion holes, a gap is formed at the d-axis end of each magnet insertion hole.   
     
     
         2 . The interior permanent magnet motor according to  claim 1 , wherein each cutout extends from the corresponding magnet insertion hole and inclines toward the outer edge with respect to the direction in which the associated magnet insertion hole extends, and each cutout is connected to the outer edge of the steel plate. 
     
     
         3 . The interior permanent magnet motor according to  claim 2 , wherein each cutout extends along the associated q-axis. 
     
     
         4 . The interior permanent magnet motor according to  claim 1 , wherein each gap is filled with plastic. 
     
     
         5 . The interior permanent magnet motor according to  claim 1 , wherein the width of each gap is less than the width of the corresponding magnet insertion hole in a direction orthogonal to the direction in which the magnet insertion hole extends, and an inner wall surface, which abuts against the corresponding permanent magnet, is formed at the d-axis end of each magnet insertion hole. 
     
     
         6 . The interior permanent magnet motor according to  claim 5 , wherein each gap is displaced to a position closer to the outer edge in a direction orthogonal to the direction in which the corresponding magnet insertion hole extends.